Recite the last two chapters of the Qur'an, remember Allah, and supplicate to Him:
And from the evil of the envier when he envies. (Qur'an 113: 5)
Hide or keep secret your affairs from the jealous person:
'O' my sons! Do not enter by one gate, but enter by different gates... (Qur'an 12: 67)
Be generous to a person who attempts to harm you, for perhaps he will then desist:
Repel evil with that which is better. (Qur'an 23: 96)
